insidious

adjective

Definition of insidiousnext
as in treacherous
formal causing harm in a way that is gradual or not easily noticed Most people with this insidious disease have no idea that they are infected. an insidious enemy

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious But there’s a historical, and some might argue insidious, irony to all of this. — Drew Pittock, USA Today, 25 July 2026 But, as Ellis demonstrates in this survey of the city’s racial history, liberal policy achievements tend to obscure more insidious forms of exclusion. — The New Yorker, New Yorker, 20 July 2026 Beneath all the splendor, the couture, the balls, and the opera lurked an undercurrent of hatred, one that would fester and erupt in ways both insidious and catastrophic. — Literary Hub, 17 July 2026 But this last year, in particular, has broken new, insidious ground. — Los Angeles Times, 16 July 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. false
  4. deceptive
  5. perfidious
  6. incorrect
  7. wrong
Adjective
  • While the unanimous support from FDA advisors boded well for Moderna’s shot, the overall path to approval was treacherous and uncertain, even until the end.
    — Beth Mole, ArsTechnica, 6 Aug. 2026
  • Fleeing an economic crisis and political repression back home, many Venezuelans have risked their lives on treacherous journeys to reach the US.
    — Rocio Munoz, CNN Money, 4 Aug. 2026
Definition of treacherous
Adjective
  • The herbal shiso adds a subtle savory depth, delivering a clean, refreshing balance to the textures and flavor.
    — Angela Hansberger, AJC.com, 7 Aug. 2026
  • Ask someone to review a two-hour video and identify subtle violations, and they are almost guaranteed to miss something.
    — Tal Lev-Ami, Forbes.com, 7 Aug. 2026
Definition of subtle
Adjective
  • Along with the WiFi jammer, deputies said they were found to be in possession of false license plates and burglary tools.
    — Dean Fioresi, CBS News, 13 Aug. 2026
  • Many of these times, KFA employees allegedly filed false expense reports chalking up the charges to meals, drinks, or standard massages.
    — Jessie Yeung, CNN Money, 12 Aug. 2026
Definition of false
Adjective
  • Violations of the law are a deceptive trade practice, which can be investigated by the state attorney general's office.
    — Seth Klamann, Denver Post, 12 Aug. 2026
  • Protection of the president has often required deft and deceptive tactics by the Secret Service.
    — Donald J. Mihalek, ABC News, 11 Aug. 2026
Definition of deceptive
Adjective
  • Logan Marshall-Green as Melanthius Melanthius is a perfidious goatherd who sides with Antinous.
    — Hannah Abraham, Forbes.com, 18 July 2026
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
Definition of perfidious
Adjective
  • The fact that the scoreboard was incorrect, Guccione told a pool reporter after the game, does not play a part in the ruling.
    — Mitch Bannon, New York Times, 11 Aug. 2026
  • The counterweight to that allure is emotional intelligence, the instinct to notice when the numbers are accurate, but the feeling is incorrect.
    — Olatunde Badmus, Forbes.com, 7 Aug. 2026
Definition of incorrect
Adjective
  • The agent that flagged a bad clause in June stops flagging it in July, and nobody did anything wrong, and nothing broke.
    — Jason Snyder, Forbes.com, 8 Aug. 2026
  • Using the wrong type of cleaning product for your tub’s material can result in scratches, discoloration, or chips.
    — Ashlyn Needham, Southern Living, 8 Aug. 2026
Definition of wrong

Browse Nearby Words

inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 13 Aug. 2026.

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Nglish: Translation of insidious for Spanish Speakers

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